The theme from “Rocky” might be one of the best ever in a sports movie. It’s symbolic of an underdog’s quest to beat overwhelming odds. It was being played as the Boston Celtics took the court prior to their game with the Milwaukee Bucks Wednesday night at the Garden.

Yeah, the “Rocky” theme for the Celtics, who won the NBA title two years ago, was brilliantly appropriate. It doesn’t matter that the Celtics will meet the Miami Heat , a team they beat three times this season, in the first round of the playoffs beginning either Saturday or Sunday. After the season that the Celtics have now completed, they’re arguably an underdog to every team they play.

After Wednesday’s 106-95 home loss to the Bucks, Doc Rivers was asked about his team’s readiness, and he promptly said that it’s ready. As if he wasn’t buying it, an interviewer asked the same question again. “What part of ‘we’re ready’ don’t you understand? We’re ready. I believe we’re ready. We’ll find it out, anyway, but, I do, I believe we’re ready to play.”

The Celtics aren’t ready. They can’t be. There is no such thing as an on/off switch, unless you want to count a 23-5 start switching to a 27-27 finish. There were plenty of reasons for the downfall.

Injuries, of course, were huge. To this day Kevin Garnett is half the player he was two years ago. Paul Pierce was hurting half the season.

False promise helped bring the Celtics down. Rasheed Wallace was disruptive and ineffective from the beginning. Marquis Daniels never rebounded from a thumb injury.

Other than Rajon Rondo, hardly anyone improved on last season. Garnett, Pierce, Ray Allen, Glen Davis, Tony Allen and Kendrick Perkins all underachieved for large chunks of the season.

An almost complete breakdown in effort was crushing. The Celtics were repeatedly beaten to loose balls and rebounds. Almost nightly, one of them explained a loss by saying “so-and-so was on fire. He couldn’t be denied.” Well, why not?

As they head into the playoffs, the Celtics are no longer the elite defensive team they once were. They were dead last in the NBA in offensive rebounds per game, dead last in technical fouls per game, too. Perkins didn’t play in the final regular-season game because Doc Rivers couldn’t afford to have him pick up a 16th technical foul, which would have meant a one-game suspension, possibly for the playoffs. The Celts were 22nd in defensive rebounds and 21st in turnovers. They slipped to ninth in defensive field goal percentage, a far drop from their accustomed 1 or 2. The team was rated 23rd in fourth-quarter points, 20th in third-quarter points.

Page 2 of 2 - They were horrible at home – 24-17. It would be halfway acceptable had they not lost to New Jersey, Washington, Toronto, Chicago and Houston, among others. They were 0-4 overall against Atlanta. They were awful against almost every young, quick, enthusiastic team.

The Celts were 18-23 against plus-.500 teams and 3-9 against Atlanta, Orlando and Cleveland. A team that two years ago allowed 16 opponents to top 100 points did so 32 times this season.

One might say, and the Celtics do, that the playoffs will be a different story. The 2005-06 Heat won a championship after winning only 52 regular-season games, and the 1994-95 champion Rockets won 47. In 1977-78 the Bullets won only 44 and took a title. The Celtics could even cite Bill Russell’s 1968-69 Celtics, who finished fourth in the Eastern Division with 48 wins, eventually taking the title. But that team came together late, winning its last four games. Its players were healthy all season, too. Now, that was turning on the switch.

The Celtics have handled the Heat this season, and they have a shot at beating them in the first round. Of course, that’s what was said when the Nets and Wizards, et. al., came to town this season. The Celtics were a mess then, and there’s no reason to think they’re any better off now.

“I think we’re ready,” Rivers said. “I mean, we have to be. It’s not like we can say ‘Can you hold up for a week and let us get ready?’ So I think we’ll be ready.”

Once Christmas came and went, the Celtics were no longer ready. They’re not any more ready now that the playoffs are here.